| Biffa Limited | Financial services | 2016 |
| Biffa Midco Limited | Financial services | 2022 |
| Biffa Municipal Limited | Water & waste | 2001 |
| Biffa Pension Scheme Trustees Limited | Extraterritorial | 1992 |
| Biffa PFI Investments Limited | Professional & scientific | 1996 |
| Biffa SRF Trading Ltd | Administrative & support | 1990 |
| Biffa Treatment Services Holdings Limited | Financial services | 2024 |
| Biffa Treatment Services Limited | Water & waste | 1989 |
| Biffa UK Group Limited | Water & waste | 1998 |
| Biffa UK Limited | Water & waste | 1998 |
| Biffa Waste Limited | Water & waste | 2000 |
| Biffa Waste Management Limited | Water & waste | 1973 |
| Biffa Waste Services Limited | Water & waste | 1969 |
| Biffa West Sussex Holdco Limited | Professional & scientific | 2009 |
| Biffa West Sussex Limited | Water & waste | 2008 |
| Big Dog Productions Ltd | Information & communication | 2023 |
| Big Electrical Contractors Limited | Construction | 2021 |
| Big Electrical Limited | Construction | 2021 |
| Big KID Industries Ltd | Manufacturing | 2021 |
| Big NAV Events Ltd | Hospitality | 2020 |
| Big NAV Florals Ltd | Wholesale & retail | 2025 |
| Big OWL Development Limited | Information & communication | 2023 |
| Big Smoke FX Ltd | Information & communication | 2023 |
| Big Stack Ltd | Administrative & support | 2012 |
| Bilas Ltd | Construction | 2008 |
| Billinge Services Limited | Professional & scientific | 2020 |
| Bilton Consulting Group Limited | Professional & scientific | 2024 |
| BIN Omran Ltd | Other services | 2016 |
| Binzaman Limited | Hospitality | 2025 |
| Biopharma Consulting Limited | Professional & scientific | 2018 |
| Birch, Hooper & Wiltshire Ltd | Construction | 2011 |
| Bird in Hand (High Wycombe) Ltd | Hospitality | 2023 |
| Birdham Court Residents Company Limited | Administrative & support | 1988 |
| Birinus Close Management Company Limited(The) | Households | 1984 |
| Birkdale Sales Unlimited | Extraterritorial | 2015 |
| Birth Baby Sleep Limited | Health & social care | 2019 |
| Birth-Ed Ltd | Education | 2024 |
| Bishops House Dental Limited | Health & social care | 2023 |
| Bism Property Ltd | Real estate | 2025 |
| BISTRO4YOU Ltd | Hospitality | 2019 |
| BIT Technologies UK Limited | Professional & scientific | 2012 |
| Bitcoin Global Capital Limited | Financial services | 2015 |
| Bite Down Limited | Hospitality | 2019 |
| Bites Limited | Information & communication | 2024 |
| Bivona Brown Limited | Arts & recreation | 2017 |
| Biznography Limited | Professional & scientific | 2010 |
| Bizorbital Ltd | Wholesale & retail | 2026 |
| Bizzcore+ Ltd | Wholesale & retail | 2025 |
| BJA Holdings Limited | Professional & scientific | 2015 |
| BJA Management Limited | Professional & scientific | 2015 |
| BJA Trading Limited | Wholesale & retail | 2005 |
| BJM Logistics Limited | Wholesale & retail | 2009 |
| BK Events Consultancy Ltd | Professional & scientific | 2016 |
| BK Executive Wycombe Limited | Transport & logistics | 2020 |
| BK Management Ltd | Professional & scientific | 2014 |
| BL Prime Scaffolding Limited | Construction | 2020 |
| Black and White Decore Ltd | Wholesale & retail | 2025 |
| Black Bamboo Creative Ltd | Administrative & support | 2017 |
| Black Bison Group Industries Limited | Manufacturing | 2020 |
| Black Cat Business Services Limited | Manufacturing | 2005 |
| Black Cat Property Ltd | Real estate | 2025 |
| Black Dog Post Production Limited | Information & communication | 2011 |
| Black Oxford Untold Stories CIC | Education | 2022 |
| Black Sea Vines Ltd | Wholesale & retail | 2025 |
| Black-Knight Business Services Limited | Information & communication | 1993 |
| Blackhorse Property Rescue Ltd | Real estate | 2017 |
| Blackjack Books Ltd | Professional & scientific | 2017 |
| Blacklaw Legal Limited | Professional & scientific | 2013 |
| Blackstone Networks Limited | Information & communication | 2021 |
| Blackstone Recovery Services Ltd | Wholesale & retail | 2025 |
| Blackstone Utilities Ltd | Professional & scientific | 2019 |
| Blackstone Worldwide Ltd | Professional & scientific | 2026 |
| Blade Recruitment Hire Ltd | Professional & scientific | 2025 |
| Blaise Designs Ltd | Professional & scientific | 2007 |
| Blanco by Lowri Ltd | Real estate | 2021 |
| Blancoburro Limited | Health & social care | 2023 |
| Blazora Ltd | Wholesale & retail | 2025 |
| Blenheim House Management Company (High Wycombe) Limited | Hospitality | 1995 |
| Blewes LLP | | 2004 |
| BLF Enterprises Limited | Real estate | 2012 |
| Blidanos Mexican Food Ltd | Hospitality | 2024 |
| Blink Couriers Ltd | Transport & logistics | 2026 |
| Blinking Beautiful Ltd | Real estate | 2020 |
| Bliss Clinic Limited | Extraterritorial | 2000 |
| Bliss Clinical Services Limited | Health & social care | 1998 |
| Blits Ltd | Information & communication | 2022 |
| BLK Thomas Ltd | Real estate | 2023 |
| Blloom Beauty Limited | Other services | 2022 |
| Bloc (UK) Limited | Other services | 2004 |
| Blockbaby Limited | Wholesale & retail | 2025 |
| Blomfield Place Residents Management Company Limited | Households | 2022 |
| Blonde’S Studio Ltd | Other services | 2023 |
| Blooming Fabulous Limited | Administrative & support | 2015 |
| Blooming Steps Early Years Limited | Health & social care | 2026 |
| BLOSSOM4U Ltd | Wholesale & retail | 2025 |
| Blowplast Limited | Manufacturing | 1988 |
| Blue Cask Data Consulting Ltd | Information & communication | 2023 |
| Blue Chip Content Limited | Arts & recreation | 2021 |
| Blue Corporate Ltd | Administrative & support | 2018 |
| Blue Frog Plumbing & Heating Ltd | Administrative & support | 2016 |